Putting in the base system basically means: create a few more tar balls
(from htdocs/$LANG/Documentation) and allow sysinst to install it.
And branch htdocs, of course (not necessarily at the same time as src).
That part is easy. How much space will that cost on distribution media?
I don't like putting any browser in the base system though, most people will
install X and a graphical one anyway. Those who don't can use one from
pkgsrc.
Martin